Human herpesvirus 8 (HHV8) is the primary viral etiologic agent in Kaposi's sarcoma (KS). However, individuals dually infected with both HHV8 and human immunodeficiency virus type 1 (HIV-1) show an enhanced prevalence of KS when compared with those singularly infected with HHV8. Host immune suppression conferred by HIV infection cannot wholly explain this increased presentation of KS. To better understand how HHV8 and HIV-1 might interact directly in the pathogenesis of KS, we queried for potential regulatory interactions between the two viruses. Here, we report that HHV8 and HIV-1 reciprocally up-regulate the gene expression of each other. We found that the KIE2 immediate-early gene product of HHV8 interacted synergistically with Tat in activating expression from the HIV-1 long terminal repeat. On the other hand, HIV-1 encoded Tat and Vpr proteins increased intracellular HHV8-specific expression. These results provide molecular insights correlating coinfection with HHV8 and HIV-1 with an unusually high incidence of KS.

Since the discovery of human herpesvirus 8 (HHV8) as a contributory cause of Kaposis sarcoma, the clinical role of this virus has been actively investigated. An understanding of HHV8 seroepidemiology is critical for the study of its pathogenesis within a specific environment. A sero-survey is described in Taiwan of 1,201 individuals ranging in age from under 1 year to over 70. Indirect immunofluorescence assay was used to determine antibody titers against both latent and lytic antigens of HHV8. The results indicate that very few individuals (3-4%) were exposed to HHV8 before 10 years of age. Infection rate peaked (19.2%) between the ages of 21 to 40. Females showed a slightly higher seroprevalence for HHV8 than males, but the difference was not statistically significant. Pregnancy did not correlate with increased HHV8 infection rate nor with augmented HHV8 antibody titers. It is concluded that HHV8 in Taiwan is predominantly an infectious agent for adults. In this geographical locale, HHV8 is similar to herpes simplex virus type 2 in its likely transmission occurring presumptively through sexual routes. However, the study also indicates that a smaller portion of HHV8-transmission could occur through nonsexual contacts.

Since the discovery of human herpesvirus 8 (HHV8) as a contributory cause of Kaposis sarcoma, the clinical role of this virus has been actively investigated. An understanding of HHV8 seroepidemiology is critical for the study of its pathogenesis within a specific environment. A sero-survey is described in Taiwan of 1,201 individuals ranging in age from under 1 year to over 70. Indirect immunofluorescence assay was used to determine antibody titers against both latent and lytic antigens of HHV8. The results indicate that very few individuals (3-4%) were exposed to HHV8 before 10 years of age. Infection rate peaked (19.2%) between the ages of 21 to 40. Females showed a slightly higher seroprevalence for HHV8 than males, but the difference was not statistically significant. Pregnancy did not correlate with increased HHV8 infection rate nor with augmented HHV8 antibody titers. It is concluded that HHV8 in Taiwan is predominantly an infectious agent for adults. In this geographical locale, HHV8 is similar to herpes simplex virus type 2 in its likely transmission occurring presumptively through sexual routes. However, the study also indicates that a smaller portion of HHV8-transmission could occur through nonsexual contacts.